1 /*
   2  * Copyright (c) 2008, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package sun.nio.ch;
  27 
  28 import java.nio.channels.spi.AsynchronousChannelProvider;
  29 import java.util.concurrent.RejectedExecutionException;
  30 import java.io.IOException;
  31 import sun.misc.Unsafe;
  32 
  33 /**
  34  * Provides an AsynchronousChannelGroup implementation based on the Solaris 10
  35  * event port framework and also provides direct access to that framework.
  36  */
  37 
  38 class SolarisEventPort
  39     extends Port
  40 {
  41     private static final Unsafe unsafe = Unsafe.getUnsafe();
  42     private static final int addressSize = unsafe.addressSize();
  43 
  44     private static int dependsArch(int value32, int value64) {
  45         return (addressSize == 4) ? value32 : value64;
  46     }
  47 
  48     /*
  49      * typedef struct port_event {
  50      *     int             portev_events;
  51      *     ushort_t        portev_source;
  52      *     ushort_t        portev_pad;
  53      *     uintptr_t       portev_object;
  54      *     void            *portev_user;
  55      * } port_event_t;
  56      */
  57     static final int SIZEOF_PORT_EVENT  = dependsArch(16, 24);
  58     static final int OFFSETOF_EVENTS    = 0;
  59     static final int OFFSETOF_SOURCE    = 4;
  60     static final int OFFSETOF_OBJECT    = 8;
  61 
  62     // port sources
  63     static final short PORT_SOURCE_USER     = 3;
  64     static final short PORT_SOURCE_FD       = 4;
  65 
  66     // file descriptor to event port.
  67     private final int port;
  68 
  69     // true when port is closed
  70     private boolean closed;
  71 
  72     SolarisEventPort(AsynchronousChannelProvider provider, ThreadPool pool)
  73         throws IOException
  74     {
  75         super(provider, pool);
  76 
  77         // create event port
  78         this.port = port_create();
  79     }
  80 
  81     SolarisEventPort start() {
  82         startThreads(new EventHandlerTask());
  83         return this;
  84     }
  85 
  86     // releass resources
  87     private void implClose() {
  88         synchronized (this) {
  89             if (closed)
  90                 return;
  91             closed = true;
  92         }
  93         port_close(port);
  94     }
  95 
  96     private void wakeup() {
  97         try {
  98             port_send(port, 0);
  99         } catch (IOException x) {
 100             throw new AssertionError(x);
 101         }
 102     }
 103 
 104     @Override
 105     void executeOnHandlerTask(Runnable task) {
 106         synchronized (this) {
 107             if (closed)
 108                 throw new RejectedExecutionException();
 109             offerTask(task);
 110             wakeup();
 111         }
 112     }
 113 
 114     @Override
 115     void shutdownHandlerTasks() {
 116        /*
 117          * If no tasks are running then just release resources; otherwise
 118          * write to the one end of the socketpair to wakeup any polling threads..
 119          */
 120         int nThreads = threadCount();
 121         if (nThreads == 0) {
 122             implClose();
 123         } else {
 124             // send user event to wakeup each thread
 125             while (nThreads-- > 0) {
 126                 try {
 127                     port_send(port, 0);
 128                 } catch (IOException x) {
 129                     throw new AssertionError(x);
 130                 }
 131             }
 132         }
 133     }
 134 
 135     @Override
 136     void startPoll(int fd, int events) {
 137         // (re-)associate file descriptor
 138         // no need to translate events
 139         try {
 140             port_associate(port, PORT_SOURCE_FD, fd, events);
 141         } catch (IOException x) {
 142             throw new AssertionError();     // should not happen
 143         }
 144     }
 145 
 146     /*
 147      * Task to read a single event from the port and dispatch it to the
 148      * channel's onEvent handler.
 149      */
 150     private class EventHandlerTask implements Runnable {
 151         public void run() {
 152             Invoker.GroupAndInvokeCount myGroupAndInvokeCount =
 153                 Invoker.getGroupAndInvokeCount();
 154             final boolean isPooledThread = (myGroupAndInvokeCount != null);
 155             boolean replaceMe = false;
 156             long address = unsafe.allocateMemory(SIZEOF_PORT_EVENT);
 157             try {
 158                 for (;;) {
 159                     // reset invoke count
 160                     if (isPooledThread)
 161                         myGroupAndInvokeCount.resetInvokeCount();
 162 
 163                     // wait for I/O completion event
 164                     // A error here is fatal (thread will not be replaced)
 165                     replaceMe = false;
 166                     try {
 167                         port_get(port, address);
 168                     } catch (IOException x) {
 169                         x.printStackTrace();
 170                         return;
 171                     }
 172 
 173                     // event source
 174                     short source = unsafe.getShort(address + OFFSETOF_SOURCE);
 175                     if (source != PORT_SOURCE_FD) {
 176                         // user event is trigger to invoke task or shutdown
 177                         if (source == PORT_SOURCE_USER) {
 178                             Runnable task = pollTask();
 179                             if (task == null) {
 180                                 // shutdown request
 181                                 return;
 182                             }
 183                             // run task (may throw error/exception)
 184                             replaceMe = true;
 185                             task.run();
 186                         }
 187                         // ignore
 188                         continue;
 189                     }
 190 
 191                     // pe->portev_object is file descriptor
 192                     int fd = (int)unsafe.getAddress(address + OFFSETOF_OBJECT);
 193                     // pe->portev_events
 194                     int events = unsafe.getInt(address + OFFSETOF_EVENTS);
 195 
 196                     // lookup channel
 197                     PollableChannel ch;
 198                     fdToChannelLock.readLock().lock();
 199                     try {
 200                         ch = fdToChannel.get(fd);
 201                     } finally {
 202                         fdToChannelLock.readLock().unlock();
 203                     }
 204 
 205                     // notify channel
 206                     if (ch != null) {
 207                         replaceMe = true;
 208                         // no need to translate events
 209                         ch.onEvent(events, isPooledThread);
 210                     }
 211                 }
 212             } finally {
 213                 // free per-thread resources
 214                 unsafe.freeMemory(address);
 215                 // last task to exit when shutdown release resources
 216                 int remaining = threadExit(this, replaceMe);
 217                 if (remaining == 0 && isShutdown())
 218                     implClose();
 219             }
 220         }
 221     }
 222 
 223     /**
 224      * Creates an event port
 225      */
 226     static native int port_create() throws IOException;
 227 
 228     /**
 229      * Associates specific events of a given object with a port
 230      */
 231     static native boolean port_associate(int port, int source, long object, int events)
 232         throws IOException;
 233 
 234     /**
 235      * Removes the association of an object with a port.
 236      */
 237     static native boolean port_dissociate(int port, int source, long object)
 238         throws IOException;
 239 
 240     /**
 241      * Retrieves a single event from a port
 242      */
 243     static native void port_get(int port, long pe) throws IOException;
 244 
 245     /**
 246      * Retrieves at most {@code max} events from a port.
 247      */
 248     static native int port_getn(int port, long address, int max, long timeout)
 249         throws IOException;
 250 
 251     /**
 252      * Sends a user-defined eventto a specified  port.
 253      */
 254     static native void port_send(int port, int events) throws IOException;
 255 
 256     /**
 257      * Closes a port.
 258      */
 259     static native void port_close(int port);
 260 
 261 
 262     static {
 263         IOUtil.load();
 264     }
 265 }